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From |
Francesco <cariboupad@gmx.fr> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: algorithmic question : running sum and computations |

Date |
Fri, 17 Aug 2012 12:30:45 +0200 |

Dear Statalist, I am stuck with a little algorithmic problem and I cannot find an simple (or elegant) solution... I have a panel dataset as (date in days) : ID DATE PRODUCT QUANTITY 1 1 A 10 1 2 A -10 1 1 B 100 1 2 B -50 1 4 C 15 1 8 C 100 1 9 C -115 1 10 C 10 1 11 C -10 and I would like to know the average time (in days) it takes for an individual in order to complete a full round trip (the variation in quantity is zero) For example, for the first id we can see that there we have ID PRODUCT delta_DATE delta_QUANTITY 1 A 1=2-1 0=10-10 1 C 5=4-9 0=15+100-115 1 C 1=11-10 0=10-10 so on average individual 1 takes (1+5+1)/3=2.3 days to complete a full round trip. Indeed I can discard product B because there is no round trip, that is 100-50 is not equal to zero. My question is therefore ... do you have an idea obtain this simply in Stata ? I have to average across thousands of individuals... :) Many, many thanks for your help and/or suggestions * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: algorithmic question : running sum and computations***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: algorithmic question : running sum and computations***From:*Scott Merryman <scott.merryman@gmail.com>

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